1. Field of the Invention
The present invention relates to recycling scrap rubber, and more particularly, to a process and apparatus for reclaiming the reusable components such as rubber, textile fibers, and metal from scrap rubber tires.
2. Description of the Prior Art
Most prior art techniques which utilize mechanical comminution of scrap rubber tires require a cryogenic treatment of the scrap before it is to be crushed or ground One of the properties of rubber is its resilience and thus the difficulty in comminuting scrap rubber tires to smaller components.
By treating the scrap by means of cryogenic gases or liquids in order to freeze the scrap, the rubber becomes brittle, allowing the scrap to be handled by conventional crushing, separating, and classifying means. Such methods are described in U.S. Pat. No. 4,025,990, issued May 31, 1977 to Lovette, Jr.; U.S. Pat. No. 4,240,587, issued Dec. 23, 1980 to Letsch; and U.S. Pat. No. 4,342,647, issued Aug. 3, 1982 to McMillan et al.
Such systems are inherently expensive since not only must the scrap tires be rid of water and ice, but all of the scrap must be frozen by cryogenic means.
At least one patent, namely, U.S. Pat. No. 4,113,186, issued Sep. 12, 1978 to Smith, attempts to mechanically separate scrap rubber tires into its major components of rubber, metal bead, and cord fabric. However, the method as disclosed in Smith, U.S. Pat. No. 4,113,186, fails to describe how the rubber component, given its inherent resilience, is efficiently handled in a hammer mill or on vibrating separating screens.